DKOL (P51) female fittings - internal thread 

Metric straight fittings with O-ring. Straight fitting with 24° cone nut and sealing ring (O-ring) according to PN-65/M-73140, PN-65/M-73141, DIN 3901, DIN 3902 standards. DKOL fittings are the most popular metric fittings found in Poland. Metric fittings are divided into two types: the light version, DKOL, and the heavy version, DKOS - the difference lies in the size of the cones inside the nut. Check: difference between DKOL and DKOS fittings. DKOL fittings have larger cones than DKOS and withstand lower pressure. Where are DKOL fittings used? DKOL fittings can be found in many sectors but are most commonly used in agricultural machinery and construction equipment. DKOL fittings can be replaced by DKL fittings (straight fittings without O-ring) It can be said that DKOL fittings are the successors to DKL fittings. DKOL fittings connect with male thread fittings of type CEL. DKOL fittings are also available in 45° elbow version DKOL45 and 90° elbow version DKOL90. The name DKOL for hydraulic fittings comes from the designations used in German standards, related to the DIN 2353 standard. The full expansion of the abbreviation and its meaning is as follows:

• D – stands for DIN, which is the German technical standard (Deutsches Institut für Normung). DKOL fittings comply with this standard.
• K – indicates the shape of the seal, which in this case is based on the use of an O-ring type sealing ring.
• O – comes from the word O-ring, i.e., the rubber ring that ensures the tightness of the connection.
• L – stands for light version (German: Leicht), as opposed to DKOS fittings, which are in the heavy version (German: Schwer).

Therefore, DKOL fittings are metric connectors in the light version, sealed with an O-ring, compliant with the DIN standard. They are widely used in hydraulic systems due to their reliability and ease of installation.

Parameters of DKOL fittings 

• Fitting construction: free-cutting steel, optionally available in stainless steel version. 
• Manufacturing standard: compliant with DIN 2353
• O-ring type seal
• Threads: from M12 to M52x2
• Thread type: metric threads